The electronic configuration of an element is 1\(s^2\) 2\(s^2\) 2\(p^6\) 3\(s^2\) 3\(p^3\). Where is the element located in the periodic table?
Trả lời
(C)
Group V, period 3
2
Group O of elements are unreactive because
Trả lời
(B)
their highest occupied enegy level is full
3
An element X with electronic configuration \(1S^22S^22P^63S^2\) combines with another element Y with the configuration \(1S^2S^22P^23S^23P^5\). What is the formula of the compound formed?
Trả lời
(D)
XY2
4
Which of the following statements about dative bonding is not correct?
Trả lời
(C)
each participating atom contributes one electron
5
Which of the following quantities is the same for one mole of Br2(l) and one mole of He(g)?
Trả lời
(A)
Number of molecules
6
Which of the following acids is dibasic?
Trả lời
(B)
Trioxosulphate (IV) acid
7
Bees inject an acidic substance when they sting. Which of the following chemical could be used to treat bee stings?
Trả lời
(B)
NaHCO3
8
Which of the following salts can be prepared by reacting the metal with dilute H2SO4?
Trả lời
(B)
MgSO4
9
Which of the following solutions will give a precipitate with dilute tetraoxosulphate (V) acid? l. Lead (ll) trioxonitrate (V) solution ll. Barium chloride solution lll. Sodium chloride solution
Trả lời
(C)
l and ll only
10
Substance Q reacts with cold water to form a solution which turns red litmus blue. Substance Q could be
Trả lời
(D)
sodium
11
What term is used to describe an oxide whose aqueous solution turns blue litmus red?
Trả lời
(B)
Acid anhydride
12
The pH of 0.50 mol dm-3 solutions of HCI, H2SO4 and CH3COOH were measured. which of the following statements about the values obtained is correct?
Trả lời
(D)
the pH value of the CH3COOH was the highest.
13
Which of the following processes involves neutralization?
Trả lời
(D)
Liming of soil
14
Sea shells contain mainly CaCO 3. Calcium oxide can be prepared from sea shells by
Trả lời
(B)
heating at a high temperature
15
Which of the following statements about an exothermic reaction is correct?
Trả lời
(A)
the products have less heat content than reactants
16
A reducing agent is expected to
Trả lời
(A)
decolourize acidified KMnO4 solution
17
Consider the electrochemical cell represented below Zn(s)/Zn2+(aq)//Cu2+(aq)/Cu(s). Which of the following equations describes the reaction occurring in the cell?
Trả lời
(C)
Zn(s) + Cu2+(aq) →Zn2+(aq) + Cu(s)
18
Five metals represented by the letters V to Z are arranged in order of their reactivity as shown . V>W>X>Y>Z.
Which of the metals cannot displace Y from an aqueous solution of its salt?
Trả lời
(D)
Z
19
Five metals represented by the letters V to Z are arranged in order of their reactivity as shown . V>W>X>Y>Z.
Which of the metals is most likely extracted by the electrolysis of its fused chloride?
Trả lời
(A)
V
20
Which of the following statements is/are correct about tin plating? l The electrolyte must be a soluble salt of tin ll. the objective to be plated is made the cathode lll. The anode is made of tin lV. The negative electrode dissolves
Trả lời
(C)
l,ll and lll only
21
Determine the amount of electrons needed to deposit 6.4g of copper during the electrolysis of copper (ll) tetraoxosulphate (IV) solution [Cu = 64]
Trả lời
(B)
0.20 mole
22
A given fuel has an octane number of 100. This means that
Trả lời
(A)
the knocking tendency of the fuel is low
23
The equation for the reaction at the anode during the electrolysis of concentrated sodium chloride solution is
Trả lời
(A)
2CI-(aq) → CI,sub>2(g) + 2e-
24
Which of the following compounds has the same empirical formula as benzene?
Trả lời
(A)
C2H2
25
A given fuel has an octane number of 100. This means that
Trả lời
(A)
the knocking tendency of the fuel is low
26
Wine containing 8% to 17% ethanol can be converted to gin containing about 40% ethanol by
Trả lời
(B)
distilation
27
Which of the following substances could be responsible for the banana taste of a food flavour?
Trả lời
(D)
Pentylethanoate
28
What is the organic product of the reaction of C2H 5OH with excess acidified K 2Cr 2O7(aq)?
Trả lời
(A)
CH3COOH
29
The reaction of vegetable oil with a solution of wood ash is
Trả lời
(A)
saponification
30
What process does the following equation represent ? n(C\(_{6}\)H\(_{10}\)O\(_{5}\)) + nH\(_{2}\)O → nC\(_{6}\)H\(_{12}\)O\(_{6}\) ?
Trả lời
(B)
Hydrolysis of starch
31
When excess ethene is shaken with acidified KMnO4 solution, the product obtained is
Trả lời
(C)
ethane - 1, 2 - diol
32
What volume of 0.20 mol dm -3 NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol-1]
Trả lời
(B)
625 cm3
33
Which of the following compound is used for removing impurities from bauxite?
Trả lời
(A)
NaOH
34
What is the main impurity in haematite?
Trả lời
(C)
SiO3
35
When a sample of water was boiled, it lathered more readily with soap. it can be concluded that the sample most likely contained
